A synthetic quartz glass for an optical member which is free from compaction and rarefaction is obtained. A synthetic quartz glass for an optical member to be used for an optical device employing a light having a wavelength of at most 400 nm and at least 170 nm as a light source, which contains substantially no oxygen excess defects, dissolved oxygen molecules nor reduction type defects, which has a chlorine concentration of at most 50 ppm and a OH group concentration of at most 100 ppm, and which contains oxygen deficient defects within a concentration range of at most 5×1014 defects/cm3 and at least 1×1013 defects/cm3. The fluorine concentration is preferably at most 100 ppm.